Carton



1962 G- v. THOMPSON 3,057,535

CARTON Filed April 4. 1960 IN V EN TOR.

ye K772079500.

WW'M

tates Unite This invention relates to a collapsible carton and moreparticularly to such a carton which is easily erected and in which thebottom has flaps formed for positive interlocking to maintain the bottomclosed and the carton in its erect condition.

An object of this invention is to provide a new and improved bottom flapconstruction for a carton in which the locking of the bottom is morepositively maintained.

Another object of this invention is to provide a carton having aplurality of interconnected side walls with each side wall having abottom flap and with one pair of opposed bottom flaps each having adiagonal score line forming each of the flaps into an inner part and anouter part with an adhesion portion, each of the adhesion portionsattached to an adjacent bottom flap of a second pair of bottom flaps,one of said outer parts having a hook portion and an opposed bottom flapof the other pair having a projecting coplanar tab whereby erection ofthe carton cause-s the tab and hook to travel toward each other with thetab passing into a slit adjacent the hook to lie behind the hook andwith said hook and tab lying in substantially the same plane when thecarton is erected to have abutment therebetween, said abutment occurringto one side of a diagonal between opposed cornets of the carton wherebyforces tending to collapse the carton maintain said abutment.

Further objects and advantages will become apparent from the followingdetailed description taken in connection with the accompanying drawingsin which:

FIG. 1 is a fragmentary plan view of the one-piece blank with the sideof the blank forming the interior of the carton uppermost.

FIG. 2 is a view similar to FIG. 1 showing initial folding of the bottomflaps preparatory to securement thereof;

FIG. 3 is a plan view of the completed carton formed from the blank andshown in collapsed condition;

FIG. 4 is an elevational view looking toward the bottom of the cartonand showing the carton in an intermediate position during erectionthereof;

FIG. 5 is a perspective view looking toward the bottom of the cartonshowing the carton in erected condition; and

FIG. 6 is a horizontal section taken generally along the line 66 in FIG.5.

While this invention is susceptible of embodiments in many differentforms, there is shown in the drawings and will herein be described indetail an embodiment of the invention with the understanding that thepresent disclosure is to be considered as an exemplification of theprinciples of the invention and is not intended to limit the inventionto the embodiment illustrated. The scope of the invention will bepointed out in the appended claims.

As shown in the drawing, a paperboard blank indicated generally at 10has a plurality of side walls indicated at 11, 12, 13 and 14 which arescoringly connected along score lines 15, 16 and 17. The side flap 11has a sealing flap 20 scoringly connected thereto along a scoreline 21whereby the carton may be formed from the blank by attachment of thesealing flap 20 to the underside of the side wall 14 and as shown inFIG. 3.

The side walls 11, 12, 13 and 14 each carry parts of structure forclosing the top of the carton after it is erected and filled. Thisstructure is shown in FIG. 3 in atent 0 3,057,535 Patented Oct. 9, 1962which the side walls 11 and 13 each carry top flaps 22 and 23,respectively, and the side walls 12 and 14 each carry a top flap 24 and25, respectively, with the top flap 24 having a hook 26 co-acting with aslit 27 cut in the top flap 25 for closing and locking the top flapstogether with the flaps 22 and 23 therebeneath.

The side walls 11 and 13 each carry a bottom flap 30 and 31 scoringlyconnected thereto by score lines 32 and 33, respectively. The bottomflaps 30 and 31 are spaced from each other with a bottom flap 34positioned therebetween and scoringly connected to a side wall 12 by ascore line 35. The bottom flap 34 along with another bottom flap 36which is connected to the side wall 14 by a score line 37 form a firstpair of bottom flaps which are opposed to each other as the carton iserected. The bottom flaps 30 and 31 constitute a second pair of bottomflaps.

Each of the bottom flaps 34 and 36 of the first pair of flaps has adiagonally extending score line 38 and 39, respectively, which divideeach of the flaps into two parts. The bottom flap 34 has inner part 40and an outer part 41 with an adhesion portion while the bottom flap 36has an inner part 42 and an outer part 43 with an adhesion portion.

In forming the carton from the blank 10, an initial step is illustratedin FIG. 2 in which the bottom flaps 30 and 31 are turned downwardly andthe bottom flaps 34 and 36 are also turned downwardly with the adhesionportions of the outer parts 41 and 43 turned upwardly along the diagonalscore lines 38 and 39 respectively. The sealing flap 20 is then broughtaround to seal against the underside of the side wall 14 and at the sametime the adhesion portion of part 41 of the bottom flap 34 is secured tothe upper side of the bottom flap 30 as viewed in FIG. 2 and theadhesion portion of part 43 of the bottom flap 46 is secured to theupper side of the bottom flap 31 as viewed in FIG. 2. This isaccomplished by known gluing operations and results in the collapsedcarton shown in FIG. 3 ready for subsequent filling upon erectionthereof.

The resulting association of bottom flaps is seen from examination ofFIG. 4 in which the car-ton is partially erected and in which pressureexerted at the score lines 15 and 17 is causing closure of the bottom ofthe carton by movement of the flaps 30 and 31 toward each other and to arelationship overlying each other across the bottom of the carton. Thisaction is obtained by the bottom flap 36 tending to move towards a flapposition which pulls the bottom flap 31 toward the bottom of the cartonand the bottom flap 34 moving also to a generally flat condition whichpulls the bottom flap 30 toward the bottom of the carton. With thebottom of the carton closed, the bottom flaps are disposed as shown inFIGS. 5 and 6. With the carton in upright condition, the bottom flap 30"ice ' is beneath the bottom flap 31 and the latter flap extends acrossthe entire bottom of the carton to form a complete closure therefor.

In order to lock the bottom flaps in position and maintain the carton inerect condition, means are provided on the bottom flaps 30 and 36including a hook 50 formed at the extremity of the outer part 43 of thebottom flap 36 and having a slit 51 adjacent thereto with the part ofthe blank material at the side of the slit remote from the hook beingfree of adhesion from the bottom flap 31. This means also includes anintegral tab 52 extending beyond the periphery of the bottom flap 30 incoplanar relation therewith and having slightly rounded corners with asubstantially straight edge 53-.

As the carton is being erected as viewed in FIG. 4, the tab 52 is causedto move toward the hook 50 and the tab 52 will pass above the book 50and through the slit 51 since the part of bottom flap 36 adjacent to theslit is free of adherence to the bottom flap 31 which tends to open theslit. With the carton bottom finally closed as viewed in FIGS. 5 and 6,the tab 52 extends to the side of the slit 51 opposite from the hook 50and the relatively straight edge 53 of the tab abuts against the edge ofthe hook 50. This abutment is maintained effective by the generallycoplanar relation between the tab 52 and the hook 50 since the hook 50lies beneath the outer part 41 of the bottom flap 34 and is thussubstantially in the same plane as the tab 52. The tab also extendsbeyond the base of the slit. This abutment also is to one side of adiagonal between opposite corners of the carton whereby forces tendingto collapse the carton maintain the locked relation between the tab 52and the book 50.

I claim:

A collapsible carton having a self-locking bottom closed andautomatically locked upon erection of the carton comprising, fourconnected side Walls with each wall having a scoringly connected bottomflap, the first and second of said bottom flaps forming a first pair ofopposed bottom flaps each having a diagonal score line forming the flapsinto an inner part and an outer part with an adhesion portion, the thirdand fourth of said bottom flaps forming a second pair of opposed bottomflaps, each being adhesively secured to one adjacent adhesion portion ofsaid first pair of opposed bottom flaps, said third bottom flap of thesecond pair having a planar projecting tab located intermediate the endsof the free edge of the flap and extending beyond the remainder of saidthird bottom flap, said tab extending beyond the edge of the adjacentfirst bottom flap when the first and third flaps are adhesively securedtogether, said tab and the adjacent edge of the first bottom flapcooperating to form a notch, and the outer part of the second bottomflap being secured to the fourth bottom flap of the second pair having ahook at its extremity and a narrow slit adjacent thereto opening towardsaid tab as the carton is erected and not adhered to the adjacent bottomflap whereby expansion of the carton causes said third and fourth bottomflaps to move toward each other as they approach parallel relation, oneabove the other, and said tab and slit approach each other with the tabpassing through said slit and lying behind said hook and between saidsecond and fourth flaps when the bottom of said carton is closed.

References Cited in the file of this patent UNITED STATES PATENTS2,017,724 Neumann Oct. 15, 1935 2,538,860 Buttery Jan. 23, 19512,659,526 Buttery Nov. 17, 1953 2,798,656 Kuchenbecker July 9, 19572,990,099 Ryder June 27, 1961

